# Pyrogram - Telegram MTProto API Client Library for Python
# Copyright (C) 2017-2018 Dan Tès <https://github.com/delivrance>
#
# This file is part of Pyrogram.
#
# Pyrogram is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Pyrogram is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with Pyrogram.  If not, see <http://www.gnu.org/licenses/>.

import pyrogram
from pyrogram.api import functions, types
from ...ext import BaseClient, utils


class GetDialogs(BaseClient):
    # TODO docstrings

    def get_dialogs(self,
                    last_chunk=None,
                    limit: int = 100):
        offset_date = 0
        offset_id = 0
        offset_peer = types.InputPeerEmpty()

        if last_chunk:
            for dialog in reversed(last_chunk.dialogs):
                top_message = dialog.top_message

                if top_message:
                    message_date = top_message.date

                    if message_date:
                        offset_id = top_message.message_id
                        offset_date = message_date
                        offset_peer = self.resolve_peer(dialog.id)
                        break

        r = self.send(
            functions.messages.GetDialogs(
                offset_date=offset_date,
                offset_id=offset_id,
                offset_peer=offset_peer,
                limit=limit,
                hash=0,
                exclude_pinned=True
            )
        )

        users = {i.id: i for i in r.users}
        chats = {i.id: i for i in r.chats}
        messages = {}

        for message in r.messages:
            if isinstance(message, (types.Message, types.MessageService)):
                chat_id = message.to_id

                if isinstance(chat_id, types.PeerUser):
                    chat_id = chat_id.user_id
                elif isinstance(chat_id, types.PeerChat):
                    chat_id = -chat_id.chat_id
                else:
                    chat_id = int("-100" + str(chat_id.channel_id))

                messages[chat_id] = utils.parse_messages(
                    self, message,
                    users, chats
                )

        dialogs = []

        for dialog in r.dialogs:
            chat_id = dialog.peer

            if isinstance(chat_id, types.PeerUser):
                chat_id = chat_id.user_id
            elif isinstance(chat_id, types.PeerChat):
                chat_id = -chat_id.chat_id
            else:
                chat_id = int("-100" + str(chat_id.channel_id))

            dialogs.append(
                pyrogram.Dialog(
                    id=chat_id,
                    top_message=messages.get(chat_id),
                    unread_messages_count=dialog.unread_count,
                    unread_mentions_count=dialog.unread_mentions_count,
                    unread_mark=dialog.unread_mark
                )
            )

        return pyrogram.Dialogs(
            total_count=getattr(r, "count", len(r.dialogs)),
            dialogs=dialogs
        )